The next step after the extraction of the MST tree and PMFG graph,
we apply the Infomap method proposed in Ref. [1]},
to investigate the community structure of the financial network.
The method is based on a random walk on the network to capture the
information flow, then to extract the community structure from the regularity of the data.
Detailed descriptions of the method are referred to Ref. [1]}.
With the Infomap method, we can identify the community
structure for both the MST tree and PMFG graph.
